1. Field of the Invention
The present invention relates to wireless communications, and more particularly, to a method for transmitting a data packet in a wireless communication system, and a wireless device using the method.
2. Related Art
3rd generation partnership project (3GPP) long term evolution (LTE) evolved from a universal mobile telecommunications system (UMTS) is introduced as the 3GPP release 8. The 3GPP LTE uses orthogonal frequency division multiple access (OFDMA) in a downlink, and uses single carrier-frequency division multiple access (SC-FDMA) in an uplink. The 3GPP LTE employs multiple input multiple output (MIMO) having up to four antennas. In recent years, there is an ongoing discussion on 3GPP LTE-advanced (LTE-A) evolved from the 3GPP LTE.
Device-to-device (D2D) communication is a distributed communication technique in which adjacent wireless nodes directly deliver traffic. In the D2D communication, a wireless node such as a mobile phone autonomously discovers another wireless node which is physically adjacent, establishes a communication session, and thereafter transmits traffic.
The D2D technique such as Bluetooth or WiFi Direct directly supports communication between wireless nodes without a support of a base station. D2D communication managed by the base station is also introduced. In this case, scheduling for the D2D communication is managed by the base station. In doing so, a traffic overload problem can be decreased by dispersing traffic concentrated to the base station.
It is proposed a method of exchanging scheduling information for the D2D communication between the wireless device and the base station.